[PATCH net 5/5] sctp: set sender next_tsn for the old result with ctsn_ack_point plus 1

[Xin Long]

When doing asoc reset, if the sender of the response has already sent some
chunk and increased asoc->next_tsn before the duplicate request comes, the
response will use the old result with an incorrect sender next_tsn.

Better than asoc->next_tsn, asoc->ctsn_ack_point can't be changed after
the sender of the response has performed the asoc reset and before the
peer has confirmed it, and it's value is still asoc->next_tsn original
value minus 1.

This patch sets sender next_tsn for the old result with ctsn_ack_point
plus 1 when processing the duplicate request, to make sure the sender
next_tsn value peer gets will be always right.

Fixes: 692787cef651 ("sctp: implement receiver-side procedures for the SSN/TSN 
Reset Request Parameter")
Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/sctp/stream.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 9dd5bfe..a20145b 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -725,7 +725,7 @@ struct sctp_chunk *sctp_process_strreset_tsnreq(
                i = asoc->strreset_inseq - request_seq - 1;
                result = asoc->strreset_result[i];
                if (result == SCTP_STRRESET_PERFORMED) {
-                       next_tsn = asoc->next_tsn;
+                       next_tsn = asoc->ctsn_ack_point + 1;
                        init_tsn =
                                sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1;
                }
-- 
2.1.0